1. Field of the Invention
The present invention relates to a method for the assisted parking of a vehicle in a parking space with the aid of a parking-assistance device that guides the vehicle along at least one parking trajectory.
2. Description of Related Art
So-called semiautomatic parking with the aid of a parking-assistance device makes it possible to guide a vehicle into a parking space, in doing which, either a steering movement may be specified by the parking-assistance device to the driver, or the parking-assistance device may actively steer the vehicle, and the driver only has to operate the gas pedal and brake pedal. The parking space in which the vehicle is to be parked may be a parallel parking space, so that in the final parked position, the vehicle is aligned parallel to the roadway on which the vehicle drives up to the parking space. If the parking space is a diagonal parking space, then in the final parked position, the vehicle is parked diagonally relative to the roadway, so that, for example, the vehicle is at an angle of approximately 45° relative to the roadway. Depending upon whether the parking space is a parallel parking space or a diagonal parking space, the objects which border the parking space are for the most part also aligned parallel to, or diagonally relative to the roadway. As a rule, the objects involve further vehicles, so that the vehicle itself must be parked so that it is offset in parallel, or is between the vehicles already parked next to one another.
Using detecting means, e.g., ultrasonic sensors, disposed laterally on the vehicle, the parking-assistance device, while the vehicle is moving slowly forward, surveys the objects which border the parking space. Based on the signal pattern ascertained, which is transmitted by the detecting means to the parking-assistance device, it is detected whether and where a suitable parking space is available relative to the vehicle. If the vehicle is pulled into a parking space which was detected by the detecting means, this may be accomplished by a move in reverse, and the parking-assistance device takes over the steering process, while the driver then only has to operate the brake and the accelerator. The parking-assistance device intervenes in the steering system of the vehicle in such a way that the vehicle to be parked is both steered past the objects bordering the parking space, and at the end of the parking maneuver, the vehicle is standing in a parallel parking space parallel to the boundary of the roadway, as a rule, the curb. In a further possible variant, the driver himself must still steer, however, the parking-assistance system communicates to the driver, what steering operation the driver must perform. In each case, however, the parking-assistance device specifies a steering motion which is either carried out semi-automatically, or is assumed by the driver.
According to a further development stage of parking-assistance devices, it is possible to park in perpendicular parking spaces, so that at the end of the parking process, the vehicle is oriented perpendicularly to the curb of the roadway. The parking-space position may be ascertained by detecting means such as ultrasonic sensors, provided laterally on the vehicle, in these systems, as well. For example, the decision as to whether a parking space is oriented in a direction parallel to or perpendicular to the roadway may be accomplished by an input by the driver, in which the driver actuates a select button in order to provide the parking-assistance device with the information as to whether the vehicle should be parked perpendicular to, or parallel to the roadway.
In the event of an operating error, for example, if the driver accidentally initiates a parallel parking operation in the case of a perpendicular parking situation really existing, with several free parking places side-by-side, the result is merely an unwanted parking alignment of the vehicle, but no collision with objects bordering the parking space is to be expected.
However, the problem of a collision arises if the choice must be made between a parallel parking space and a diagonal parking space. Diagonal parking spaces can only be distinguished from perpendicular parking spaces to a very limited extent by the detecting means as the vehicle passes the diagonal parking spaces, which is why the driver is integrated into the decision process. If the driver makes an error in selecting the type of parking space, and mistakenly selects a parallel parking space instead of a diagonal parking space, then with high probability, the vehicle will collide with an object bordering the parking space, as a rule, with a further vehicle.
A method for the assisted parking of a vehicle in a parking space with the aid of a parking-assistance device is already known from the German Patent application 10 2007 027 438 A1. In that case, detecting means are used which communicate the distances to the objects bordering the parking space in the form of data records to the parking-assistance device. A steering motion may be initiated or specified on the basis of these data records. As a result, therefore, a vehicle is able to be pulled exactly into a perpendicular parking space.
Published German patent application document DE 10 2006 052 575 A1 describes a further method for the assisted parking of a vehicle in a perpendicular parking space with the aid of a parking-assistance device, in doing which, the parking process may be assisted automatically with the fewest possible operating actions by the driver, even if, for instance, the parking space is not adequately ascertainable with respect to the depth measured relative to the direction of travel of a roadway. In this context, an automatic parking mode may also be activated directly without an input by the driver to actuate a parking process, providing the obstacles and/or open spaces sensed by a detecting means in a parking space have been ascertained reliably. An angle between a longitudinal direction of the vehicle and a front end of the parking space represents one criterion which may be utilized to determine whether parallel parking or perpendicular parking is desired on the part of the driver. If the driver stops the vehicle at an angle of the longitudinal axis relative to the front of the parking space which exceeds what is referred to as a triggering angle, it may then be assumed that the driver intends to park perpendicularly. It is further proposed that the driver confirmation input is only provided if an angle between the longitudinal direction of the vehicle and a front of the parking space exceeds a predefined triggering angle.
However, the known methods are unable to overcome the danger that a collision may occur with the objects bordering the parking space due to a false input by the driver to the parking-assistance device when selecting between a parallel parking space and a diagonal parking space.
Therefore, an object of the present invention is to provide a method for the assisted parking of a vehicle in a parking space with the aid of a parking-assistance device which overcomes the disadvantages of the related art cited above, and permits collision-free parking in a parking space which may be in the form of a parallel parking space or a diagonal parking space.